Tailpipe collar

ABSTRACT

An exhaust system for a vehicle may include a tailpipe and a collar. The tailpipe may be adapted to receive exhaust gas from an internal combustion engine and may include an outlet. The collar may include an inner surface, an outer surface, an air-inlet, and an air-outlet. The inner surface may be radially spaced apart from the tailpipe and may at least partially surround the outlet of the tailpipe. The inner and outer surfaces may be shaped to form a profile that causes a first air-flow to accelerate upon flowing between the inner surface and the tailpipe to a first velocity that is faster than a second velocity of a second air-flow. The second air-flow may be flowing adjacent the outer surface and radially outward relative to the outer surface.

FIELD

The present disclosure relates to collar for an exhaust tailpipe of a vehicle.

BACKGROUND

A vehicle may include an internal combustion engine and an exhaust system receiving exhaust gas from the internal combustion engine. While conventional exhaust systems can reduce noise and remove pollutants from the exhaust gas prior to being discharged into the atmosphere, backpressure in the exhaust system can impede the power output and efficiency of the engine. Specifically, backpressure in the exhaust system can restrict expulsion of exhaust gas from a combustion chamber and hinder induction of an air-fuel mixture into the combustion chamber.

SUMMARY

The present disclosure provides an exhaust system for a vehicle that may include a tailpipe and a collar. The tailpipe may be adapted to receive exhaust gas from an internal combustion engine and may include an outlet. The collar may include an inner surface, an outer surface, an air-inlet, and an air-outlet. The inner surface may be radially spaced apart from the tailpipe and may at least partially surround the outlet of the tailpipe. The inner and outer surfaces may be shaped to form a profile that causes a first air-flow to accelerate upon flowing between the inner surface and the tailpipe to a first velocity that is faster than a second velocity of a second air-flow. The second air-flow may be flowing adjacent the outer surface and radially outward relative to the outer surface.

A first pressure of fluid between the air-inlet and the air-outlet may be lower than a second pressure of fluid upstream of the outlet of the tailpipe.

In some embodiments, the inner and outer surfaces form an annular portion that may extend angularly around the entire outlet of the tailpipe. In other embodiments, the inner and outer surfaces may extend angularly around only a portion of the outlet of the tailpipe.

In some embodiments, the inner surface of the collar may curve radially inward, and may cooperate to form an airfoil. The airfoil may include a chord line that may be disposed at a two-degree angle relative to a longitudinal axis of the collar.

In some embodiments, the collar may include at least one support member extending radially between the tailpipe and the inner surface. The collar may include an inner ring that may be attached to the at least one support member and engaging the tailpipe.

In some embodiments, the outlet of the tailpipe may include a nozzle portion.

In another form, the present disclosure provides a tailpipe collar that may include an outer ring and a spoke. The outer ring may be configured to least partially surround a tailpipe of a vehicle. The outer ring may include an inner surface and an outer surface that cooperate to form an airfoil-shaped cross section. The spoke may be connected to the outer ring and may extend radially inward therefrom. The spoke may be adapted to support the outer ring relative to the tailpipe.

In some embodiments, the tailpipe collar may include an inner ring adapted to engage and at least partially surround the tailpipe. The outer ring may be disposed radially outward relative to the inner ring. The spoke may extend between the inner and outer rings and may be attached to the inner and outer rings.

In some embodiments, an outlet of the tailpipe may be disposed between an air-inlet and an air-outlet defined by the outer ring and the outer ring receives exhaust gas from the outlet of the tailpipe. The outer ring may receive air through the air-inlet when the vehicle is moving in a forward direction. In some embodiments, the outer ring and/or the inner ring may be substantially circular.

Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings provided hereinafter. It should be understood that the summary and detailed description, including the disclosed embodiments and drawings, are merely exemplary in nature intended for purposes of illustration only and are not intended to limit the scope of the invention, its application or use. Thus, variations that do not depart from the gist of the disclosure are intended to be within the scope of the invention.

When an element or component is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or component, it may be directly on, engaged, connected or coupled to the other element or component, or intervening elements or components may be present. In contrast, when an element or component is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or component, there may be no intervening elements or components present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed herein could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a vehicle including a tailpipe and tailpipe collar according to the principles of the present disclosure;

FIG. 2 is a perspective view of the tailpipe and tailpipe collar of FIG. 1;

FIG. 3 is a rear view of the tailpipe and tailpipe collar of FIG. 1;

FIG. 4 is a cross-sectional view of the tailpipe and tailpipe collar at Line 4-4 in FIG. 3;

FIG. 5 is a cross-sectional view of a combustion chamber of an engine of the vehicle of FIG. 1;

FIG. 6 is a cross-sectional view of another tailpipe and tailpipe collar according to the principles of the present disclosure;

FIG. 7 is a cross-sectional view of yet another tailpipe and tailpipe collar according to the principles of the present disclosure; and

FIG. 8 is a rear view of still another tailpipe and tailpipe collar according to the principles of the present disclosure.

DETAILED DESCRIPTION

In an exemplary embodiment and with reference to FIGS. 1-5, a vehicle 10 is provided that may include an engine 12 and an exhaust system 14. The engine 12 may be an internal combustion engine including one or more combustion chambers 2 partially defined by a piston 3, as shown in FIG. 5. Each combustion chamber 2 includes one or more intake ports 4 and one or more exhaust ports 6. Fluid flow through the intake and exhaust ports 4, 6, are controlled by intake and exhaust valves 7, 8, respectively. An air-fuel mixture is drawn into the combustion chamber 2 through the intake port 4 for combustion therein. Exhaust gas is discharged from the combustion chamber 2 through the exhaust port 6 and subsequently flows through the exhaust system 14 and is discharged to the ambient environment. It will be appreciated that in some embodiments, the vehicle 10 may be a hybrid vehicle including an electric motor in addition to the engine 12.

The exhaust system 14 may include an exhaust pipe 16, a muffler 18, a tailpipe 20, and a tailpipe collar 22. Exhaust gas discharged from the engine 12 may flow through the exhaust pipe 16, through the muffler 18, and may exit through the tailpipe 20. As will be subsequently described, the tailpipe collar 22 may generate a low-pressure region downstream of the tailpipe 20 that draws exhaust gas out of the tailpipe 20 and generates a pressure-gradient across the exhaust system 14 that may reduce backpressure in the exhaust system 14 and may improve induction of an air-fuel mixture into the engine 12.

The tailpipe collar 22 may include a inner ring 24, one or more spokes 26, and an outer ring 28. The tailpipe collar 22 can be molded or otherwise formed from a metallic and/or polymeric material, for example. The inner ring 24 may be welded, staked, and/or otherwise fixed to an outer surface 30 the tailpipe 20 at or near an outlet 32 of the tailpipe 20. In some embodiments, the inner ring 24 could be integrally formed with the tailpipe 20.

The spokes 26 may extend radially between and interconnect the inner ring 24 and the outer ring 28. The spokes 26 may be substantially rigid support members that may position the outer ring 28 such that it is generally coaxial with the inner ring 24 and the tailpipe 20. It will be appreciated that in some embodiments, the tailpipe collar 22 may not include an inner ring 24. In such embodiments, the spokes 26 may be directly connected to or integrally formed with the outer surface 30 of the tailpipe 20.

The outer ring 28 may be radially spaced apart from the outer surface 30 of the tailpipe 20 and may at least partially surround the outlet 32 of the tailpipe 20. The outer ring 28 may include an inner surface 34 and an outer surface 36. The inner and outer surfaces 34, 36 may cooperate to form an airfoil cross-sectional profile (shown best in FIG. 4) having a leading edge 38 and a trailing edge 40. The leading edge 38 may define an airfoil inlet, and the trailing edge 40 may define an airfoil outlet. In some embodiments, the cross-sectional profile may be a Clark Y airfoil profile, for example.

In some embodiments, an angle-of-attack of the airfoil profile may be about two degrees, for example. The angle-of-attack may be defined as an angle between a longitudinal axis A (FIG. 4) of the tailpipe collar 22 and a chord line C. The chord line C may be defined as a line connecting the leading edge 38 and the trailing edge 40. It will be appreciated that in other embodiments, the angle-of-attack could be more or less than two degrees.

In some embodiments, a diameter D1 (measured at the trailing edge 40) of the outer ring 28 may be sized relative to an inner diameter D5 of the tailpipe 20 and an outer diameter D6 of the inner ring 24 such that the square of the diameter D1 minus the square of the diameter D6 is less than the square of the diameter D5 (i.e., D1 ²−D6 ²<D5 ²). It will be appreciated that while the outer ring 28 is shown in FIGS. 2-4 as being a substantially circular annular member, in some embodiments, the outer ring 28 could be oblong, teardrop-shaped, polygonal, or any other shape. In some embodiments, the outer ring 28 may extend only partially around the periphery of the tailpipe 20.

During operation of the engine 12 and while the vehicle 10 is moving in a forward direction F (FIG. 1), ambient air surrounding the exhaust system 14 may flow through the outer ring 28. That is, air reaching the leading edge 38 may flow around the outer surface 36 of the outer ring 28 and between the inner surface 34 of the outer ring 28 and the outer surface 30 of the tailpipe 20, as shown in FIG. 4.

At a given speed of the vehicle 10 in the forward direction F, airflow upstream of the leading edge 38 may be at a first velocity V1 and a first air pressure P1. The first velocity V1 may be approximately equal to the speed of the vehicle 10. Upon reaching the leading edge 38, the airflow may split into a first portion that flows between the outer ring 28 and the tailpipe 20 and a second portion that flows adjacent the outer surface 36 of the outer ring 28 (i.e., radially outward relative to the outer surface 36). The first portion of air that flows between outer ring 28 and the tailpipe 30 may accelerate to a second velocity V2. The second portion of air that flows adjacent the outer surface 36 may flow at a third velocity V3. Downstream of the trailing edge 40, the first and second portions of airflow may rejoin each other and flow at the first velocity V1 and the first pressure P1. Due to the airfoil-shaped cross-sectional profile of the outer ring 28, the second velocity V2 is greater than the third velocity V3.

The difference in airflow velocities V2, V3 result in pressure differentials between an area bounded by the inner surface 34 and areas outside of the outer ring 28 such that the airflow adjacent the inner surface 34 is at a second air-pressure P2 and the airflow outside of the outer ring 28 is at a third air-pressure P3. According to principles of aerodynamic lift, the second air-pressure P2 will be less than the first air-pressure P1 and the third air-pressure P3 because the second velocity V2 is greater than the first and third velocities V1, V3.

Exhaust gas in the tailpipe 20 upstream of the outlet 32 may be at a pressure P5. The pressure P5 is determined by the speed of the engine 12. The air flowing adjacent the inner surface 34 at the second air-pressure P2 may combine with the exhaust gas from the tailpipe 20 downstream of the outlet 32 at another pressure P4. The pressure P4 may be lower than the pressure P5, but higher than the second air-pressure P2. The relatively low pressure P4 downstream of the outlet 32 of the tailpipe 20 creates a pressure differential between fluid upstream of the outlet 32 and downstream of the outlet 32. This pressure differential draws exhaust gas through the exhaust system 14 and out of the outlet 32, thereby increasing a flow rate of exhaust gas through the exhaust system 14 and reducing backpressure in the exhaust system 14.

As described above, the tailpipe collar 22 may be operable to improve induction of the air-fuel mixture into the combustion chamber 2. This is because in some embodiments, valve timing of the engine 12 may be configured such that both the intake and exhaust valves 7, 8 may be in open positions (as shown in FIG. 5) when the piston 3 is at or near top-dead-center during the end of the exhaust stroke of the piston 3 and/or during the beginning of the intake stroke of the piston 3. When both the intake and exhaust valves 7, 8 are simultaneously open, the relatively low pressures P2, P4 drawing exhaust gas through the exhaust system 14 and the exhaust port 6 can cause a scavenging effect which lowers pressure downstream of the intake port 4, which draws the air-fuel mixture into the combustion chamber 2. This phenomenon can increase an amount of the air-fuel mixture entering the combustion chamber 2, thereby improving the power and efficiency of the engine 12.

With reference to FIG. 6, another tailpipe 120 and tailpipe collar 122 are provided. The tailpipe 120 and the tailpipe collar 122 may be incorporated into the vehicle 10 in the manner described above. The structure and function of the tailpipe 120 and the tailpipe collar 122 may be substantially similar to the tailpipe 20 and tailpipe collar 22 described above, apart from any exceptions described below and/or shown in the Figures.

The tailpipe 120 may include an outlet portion 132 that is necked down to form a nozzle. The nozzle may increase a velocity of the exhaust gas exiting the tailpipe 120.

The outer ring 128 of the tailpipe collar 122 may be tapered such that a diameter of the outer ring 128 at a leading edge 138 is substantially greater than a diameter of the outer ring 128 at a trailing edge 140. This configuration of the outer ring 128 may increase the velocity of the air flowing between the outer ring 128 and the tailpipe 120 and reduce the pressure downstream of the tailpipe 120.

With reference to FIG. 7, another tailpipe 220 and tailpipe collar 222 are provided. The tailpipe 220 and the tailpipe collar 222 may be incorporated into the vehicle 10 in the manner described above. The structure and function of the tailpipe 220 and the tailpipe collar 222 may be substantially similar to the tailpipe 20 and tailpipe collar 22 described above, apart from any exceptions described below and/or shown in the Figures.

The tailpipe collar 222 may include an inner ring 224, one or more spokes 226, and an outer ring 228. The inner ring 224 may be sized and positioned relative to the tailpipe 220 such that a portion of the inner ring 224 extends beyond an outlet 232 of the tailpipe 220. A distal end 225 of the inner ring 224 may be tapered radially inward to form a nozzle. In this manner, an effective length of the tailpipe 220 may be increased and a nozzle may be added to a standard straight-walled tailpipe.

With reference to FIG. 8, another tailpipe 320 and tailpipe collar 322 are provided. The tailpipe 320 and the tailpipe collar 322 may be incorporated into a vehicle having a rear bumper or fascia 300. The tailpipe 320 and tailpipe collar 322 may be partially nested in a recessed portion 301 of the rear fascia 300. The structure and function of the tailpipe 320 and the tailpipe collar 322 may be substantially similar to the tailpipe 20 and tailpipe collar 22 described above, apart from any exceptions described below and/or shown in the Figures.

The tailpipe collar 322 may include an inner ring 324, one or more spokes 326, and an outer portion 328. The outer portion 328 may include an upper portion 360 and a lower portion 362 forming a teardrop shape. The upper portion 360 may directly contact the inner ring 324 or an outer surface 330 of the tailpipe 320. The lower portion 362 may extend downward from the upper portion 360 and may be spaced apart from the inner ring 324 and the outer surface 330 of the tailpipe 320. The lower portion 362 may include an airfoil cross-sectional profile, for example, or any other profile shape that causes air to flow between the tailpipe 320 and the lower portion 362 at a higher velocity than air flowing outside of the outer portion 328.

It should be appreciated that in some embodiments, the outer portion 328 may not include the upper portion 360. In such embodiments, the lower portion 362 may extend directly from the inner ring 324 or the outer surface 330 of the tailpipe 320. 

What is claimed is:
 1. An exhaust system for a vehicle comprising: a tailpipe adapted to receive exhaust gas from an internal combustion engine and including an outlet; and a collar including an inner surface, an outer surface, an air-inlet, and an air-outlet, the inner surface being radially spaced apart from the tailpipe and at least partially surrounding the outlet of the tailpipe, the inner and outer surfaces being shaped to form a profile that causes a first air-flow to accelerate upon flowing between the inner surface and the tailpipe to a first velocity that is faster than a second velocity of a second air-flow flowing adjacent the outer surface and radially outward relative to the outer surface.
 2. The exhaust system of claim 1, wherein a first pressure of fluid between the air-inlet and the air-outlet is lower than a second pressure of fluid upstream of the outlet of the tailpipe.
 3. The exhaust system of claim 1, wherein the inner and outer surfaces form an annular portion that extends angularly around the entire outlet of the tailpipe.
 4. The exhaust system of claim 1, wherein the inner and outer surfaces extend angularly around only a portion of the outlet of the tailpipe.
 5. The exhaust system of claim 1, wherein the inner surface of the collar curves radially inward.
 6. The exhaust system of claim 1, wherein the inner and outer surfaces of the collar cooperate to form an airfoil.
 7. The exhaust system of claim 1, wherein an angle between a chord line of the airfoil and a longitudinal axis of the collar is about two degrees.
 8. The exhaust system of claim 1, wherein the collar includes at least one support member extending radially between the tailpipe and the inner surface.
 9. The exhaust system of claim 8, wherein the collar includes an inner ring attached to the at least one support member and engaging the tailpipe.
 10. The exhaust system of claim 1, wherein the outlet of the tailpipe includes a nozzle portion.
 11. A tailpipe collar comprising: an outer ring configured to least partially surround a tailpipe of a vehicle, the outer ring including an inner surface and an outer surface that cooperate to form an airfoil-shaped cross section; and a spoke connected to the outer ring and extending radially inward therefrom, the spoke adapted to support the outer ring relative to the tailpipe.
 12. The tailpipe collar of claim 11, further comprising an inner ring adapted to engage and at least partially surround the tailpipe, the outer ring being disposed radially outward relative to the inner ring, the spoke extending between and attached to the inner and outer rings.
 13. The tailpipe collar of claim 11, wherein an outlet of the tailpipe is disposed between an air-inlet and an air-outlet defined by the outer ring and the outer ring receives exhaust gas from the outlet of the tailpipe.
 14. The tailpipe collar of claim 13, wherein the outer ring receives air through the air-inlet when the vehicle is moving in a forward direction.
 15. The tailpipe collar of claim 11, wherein a first pressure of fluid between the air-inlet and the air-outlet is lower than a second pressure of fluid upstream of the outlet of the tailpipe.
 16. The tailpipe collar of claim 11, wherein the outer ring extends angularly around the entire outlet of the tailpipe.
 17. The tailpipe collar of claim 11, wherein the outer ring extends angularly around only a portion of the outlet of the tailpipe.
 18. The tailpipe collar of claim 11, wherein the inner surface of the outer ring curves radially inward.
 19. The tailpipe collar of claim 11, wherein the outer ring is disposed at an angle-of-attack of about two degrees.
 20. The tailpipe collar of claim 11, wherein the outer ring is substantially circular. 